This is my first subwoofer project for the home. I have done LOTS of reading but I wanted to see what people thought of my plans so far. I was using winisd to model the enclosure and gathered that, in general for sealed boxes, larger is better. I want two separate subwoofers that will be placed in two different locations and they will double as end tables, essentially. So size is not of too much concern except when it comes time to move to a new place! I was thinking of a 4 cubic foot box for each 10" driver. WinISD shows a -3 dB point of 41.85 Hz for a single driver and -6 dB of 29 Hz.

The amplifier:
These drivers can handle quite a lot of power (350Wrms). I found a Dayton rack mount amp from Part-Express that puts out 1000Wrms into 4 ohms. So two 8 ohm subwoofers in parallel, each could potentially get 500Wrms. I own an oscilloscope so setting the level would not pose a problem. The price is low for this amplifier but it has a lot of features that I like, mainly the EQ. There also isn't much information about this amplifier online so I'm concerned about its quality.

What do you guys think? It seems simple, right?

I just sold my old subwoofer (axiom EP350) on ebay because I hated its ported sound and the fact that it never turned on unless it was playing very loud. I listen to a lot of music and sometimes movies.

Thanks!

richie00boy

3rd September 2007 04:54 PM

No bigger is not always better. That box is probably ten times as big as it needs to be for no gain, power handling will be quite poor.

The only way to use these drivers sealed is to add EQ such as a Linkwitz Transform. They are intended to be coupled with their partnering passive radiator in a small box.

Don't tar all ported/PR designs with the same brush because you heard one you didn't like ;)

They appear to recommend a sealed enclosure for this driver. I have heard some good PR setups but they are more expensive since they inherently require more parts. I haven't heard any good ported subs that I like, I think its a matter of taste perhaps. Can you explain why the power handling would be poor with a 4 cf enclosure?

Tymphany recommends a 62 ltr enclosure for a f-3 of about 40 Hz but when I put that into winISD it shows 34 Hz. I checked the parameters... What could I be doing wrong here? maybe the fill is modeled in their calculations???

I know EQ is necessary for a sealed box, hence my interest in the parts-express amp. My room is fairly small too, the longest dimension is 17 ft. Room gain will come into play.

bjorno

5th September 2007 01:08 PM

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Quote:

The only way to use these drivers sealed is to add EQ such as a Linkwitz Transform. They are intended to be coupled with their partnering passive radiator in a small box.

I believe this statement concerns the older XLS drivers and more often not needed for the newer XXLS types.

Quote:

Here are Tymphany's application notes for the 8 ohm XXLS I was referring to: http://www.tymphany.com/datasheet/appview.php?id=30 They appear to recommend a sealed enclosure for this driver. ….Can you explain why the power handling would be poor with a 4 cf enclosure?

Your referring link goes to an application for a 12” driver but in your first posting you wrote:

Two XXLS drivers (black cone) suitable for closed application exists, the 12” 830845 and the 10” 830843, booth drivers are good performers in a 4 cu ft closed box. See picture 1(2)

I think the power handling is quite adequate for both the XXLS 12” 830845 and the 10” 830843 when used in a small room, especially if doors are closed with an expected lowest modal frequency (your room) of about 33 Hz (17 ft).

Quote:

Tymphany recommends a 62 ltr enclosure for a f-3 of about 40 Hz but when I put that into winISD it shows 34 Hz. I checked the parameters... What could I be doing wrong here? maybe the fill is modeled in their calculations???

Looks like an error in the paper, fc is about 40-41 Hz but f3 and should be about 35 Hz when no stuffing.

Both fc and f3 would lower about an Hz if stuffed (Vb magnified by 15%). See picture 2(2)

b

1(2)

bjorno

5th September 2007 01:10 PM

2 Attachment(s)

2(2)

richie00boy

5th September 2007 01:36 PM

Sorry, yes I missed the additional X in the product name.

cava

14th September 2007 05:26 PM

I picked up a Crown XTI-1000. I decided to save some money and just build one 12" peerless XXLS for the time being. Thinking of the future, if I plan to have an identical unit I would like to run each on a separate channel so I could adjust everything independently (gain, EQ, crossovers, etc.). But the XTI-1000 puts out 275W per channel into 8 ohms. I'm trying to avoid bridging the channels even though I realize that would give me adequate power. Are there any tests around for this amplifier? I found a post where someone had linked to a test of some behringer amps and others but I can't find it now... I just want to see if maybe the crown can drive the peerless easily at 8 ohms (capable of 350W).